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- Apr 12th 2008, 06:22 PMKrizalidToday's calculation of integral #9
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- Apr 12th 2008, 09:24 PMMathstud28Ok
- Apr 13th 2008, 06:20 AMKrizalid
- Apr 13th 2008, 09:01 AMThePerfectHacker
I did not solve it yet. Here is the first step I was thinking. Let .

This gives us, . - Apr 13th 2008, 09:04 AMMoo
Hello,

Let

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If x=0 then

If x=1 then

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Inverting the extremities of the integral with the - sign coming from du

Where did i go wrong ? :'( - Apr 13th 2008, 09:08 AMThePerfectHacker
- Apr 13th 2008, 09:11 AMMoo
Actually, i've been trying but gave up an hour ago... The first parts of integration by parts were divergent oO

And ok, when i posted i saw the first version of your integral and got anxious because it was not the same... - Apr 13th 2008, 09:23 AMMathstud28So is it this?
- Apr 13th 2008, 09:33 AMMoo
Yop,

Where did go ? :p (it's it, instead of +1)

But your method doesn't simplify the problem... or i've missed a point ^^ - Apr 13th 2008, 09:38 AMMathstud28oops
- Apr 13th 2008, 11:26 AMKrizalid
- Apr 16th 2008, 07:22 PMKrizalid
Hint: construct a double integral. (Following on post #4.)

- Apr 26th 2008, 01:06 PMKrizalid
What we need is From there you may observe that the conclusion follows.

- Apr 27th 2008, 05:45 PMThePerfectHacker
- Apr 29th 2008, 09:39 AMThePerfectHacker
In general, for and . This seems to be a useful fact to know in double integration.